Post-nerf veigar is much like Mini Mario
Mini mario has some advantages over his normal-sized self. He jumps higher, can walk on water, and can enter tiny pipes. Veigar has advantages over his pre-nerf self, such as longer ranged Q and double AP farm. Mini mario does have disadvantages, however. He can still kill enemies, but it takes more effort and skill. You can only ground pound to do any damage (pressing down in mid-air). Veigar is the same way. He can still kill his enemies, but it takes much more effort and skill.
Just a nice comparison I found.
:)